1. Field of the Invention
The present invention relates to farm implements and, more particularly, to an apparatus for supplying particulate material such as seed, fertilizer, herbicide or insecticide to one or more tanks of an air seeder. The invention may also be used with other farm implements having pneumatic material conveying systems such as a planter or fertilizer application equipment.
2. Description of the Related Art
Air seeder systems include a traction unit with an air cart in tow and frequently include a third unit such as a cultivator either between the traction unit and air cart, or towed behind the air cart. Agricultural implements that employ an air seeder system to apply seed, fertilizer, or other particulate material, either sub-surface or to the surface of a farm field, typically have a material supply source such as one or more tanks that are loaded with the particulate material. The tanks have or are associated with a metering device, which typically consists of a rotating element, which meters the particulate material from the tanks into a set of distribution channels, such as conduits, hoses, etc., for application to the farm field. In most systems, a pneumatic source such as a fan or blower provides air to convey and distribute material through the distribution channels. Some row planters employ a similar air distribution system to supply seeds to the individual row unit hoppers.
In some cases, the apportionment of airflow among the distribution channels is uneven. By design, some fans, radial fans for example, produce an uneven distribution of air near the outlet. The uneven distribution leads to skewed distribution profiles for pressure and flow rate at the outlet of the fan's plenum. This can lead to preferential air flow, uneven seed distribution during seeding and could cause plugging of seed lines.
A uniform air flow profile and a concave profile for pressure distribution would be ideal. These two profiles are not identical. To meter a specified amount of product, a minimum level of air flow needs to be met in all distribution lines. Some distribution lines are longer and those lines require more pressure to combat the hose length dependent pressure loss.
What is needed in the art is an air distribution system which meets the forgoing requirements.